Hi Guennadi-san, 2012/02/04 0:43, Guennadi Liakhovetski wrote: > The current renesas_usbhs driver triggers > > BUG: scheduling while atomic: ksoftirqd/0/3/0x00000102 > > with enabled CONFIG_DEBUG_ATOMIC_SLEEP, by submitting DMA transfers from > an atomic (tasklet) context, which is not supported by the shdma dmaengine > driver. Fix it by switching to a work. Also simplify some list > manipulations. > > Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@xxxxxx> > --- > > Shimoda-san, this is the problem, that you were observing. However, it > exists with the present version of shdma just as well as with the new one > - on top of the simple DMA library. I marked it an RFC because (1) I only > lightly tested it with the gadget device on mackerel with the mass storage > gadget, and (2) I am somewhat concerned about races. Currently the work > function runs with no locking and there are no usual cancel_work_sync() > points in the patch. However, it has also been like this before with the > tasklet implementation, which is not much better, and it looks like there > are no asynchronous operations on the same packets like timeouts. Only > asynchronous events, that I can think about are things like unloading the > driver or unplugging the cable, but these have been there before too. It > would become worse on SMP, I think. Comments welcome. Thank you for the patch and comments. I also tested this patch using the g_mass_storage and g_ether. About your points, I think so, too. So, I will write such a code. Best regards, Yoshihiro Shimoda -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
